Switch-contact structure



March l0, 1931. W K RiANKlN 1,796,217

SWITCH CONTACT STRUCTURE Filed Feb. 28. 1930 Inventor: Wil lrrn K amkin, E55 His At o'vne'g.

portions 12o with'upon subsequent in theifollowin i n usual adapter 'structure 2 which Isupports the l'Pa'.t'ented 1(4),l 1931 i' l umTEnsrAras PATENT ,OFFICE WILLIAM x. or arsnowNE, 'rnrumsiimagini, AssreNon 'ro `arruinar. ELEG- Tmc comm, A CORPORATION or NEW vom:

ypplication -1ed Februa;y 28,1930. SerialNo. 432,245. My invention relates tb. switch contact structure, and more particularly to contact structure for lar e capacity circuit breakers of the iiuid-brea tyr.

When switches of t e fluid-break type, as` oil circuitjbreakers, are us`ed to interrupt large power currents,the contacting surfaces of the'switch and associated parts may be severely. burned by the efectsof arcing so. 10 that good conducting engagement is not A,ob-

tained unlessthe switch parts are frequently replaced. the usual contact rod and segment arrangement, the arc is drawn between the end of the contact rod and the adjacent j of the segments upon opening ofthe breaker, with the'result that the segments ,are often burned and coated with anoxide film in parts so that.l the contact rodj is unable to make aclean conducting engagement thereclosing the stationary contact structure. The cylindrical member 5'is provided with an opening at' lower end' within which having an outwardly ared opening 7 through whi h the movable contact rod 8 may move to make and break the circuit within the chamberq the explosion chamber is provided Wit sulating and reinforcing structure, inc ud ing a platel 9 upon which the outer cylindri- .cal insulating shield 10 is mounted. "An insulating lining likewise disposed within-the explosion chamber. The exact details of construction of the explosion'c amber form nopart of my closure of the switch.' present invention, which may be incorpo- Itis a principal objectof my invention to rated in an explosion chamber of any well known construction.

`,Mounted within the\explosion'chamber is the coacting contact structure forthe contact provide an improved ,switch contactv structure, particularly useul for switchesof the luid-breaktype, which shall be simple and 95 rugged in construction and efficient, inl operation, and which, shall localize the effects of burning so as to obtain clean conducting engagement between the switch parts.

-My invention will be more fully set forth 4 description referring .to the accompanying, rawing, and the features oi novelty which characterize my invention will /be pointedout `with particularity in the claims annexed to and vforining a partof this 35 specification. I, x

' Referring to theldrawing, the single igure thereof is Van elevational cross-'sectional view of a portion of a circuit breaker embodying myinvention. 9 'u Q 41.9

' By way of example, but without limitation thereto, my invention is illustrated as emlpositlon wherein the liange 2 3 -bodied in an oil circuit breaker of the ex@ yA-member engages the limiting shoulder 16. l. plosion chamber type comprisingI a lead-inf For the pur ose lotsupporting conducting conductor 1 electrically connected I' to the means adapte to engage the contact member, the contact retainingmeans likewise in; cludes a shell-like member ,24 which is suit retaining means inclu .mg a member 12 having an annular iiange 13 for securing the same, as by the bolts 1A, to the cover m'ember 4 of the chainber. The member 12 comprises a cylindrical portion 15, which ex tends through the cove yplate1ahaving an portion 17 within,which a contact member 18 is; guided forreciprocal movement. contact member 18 which-may benc lindri- Acal in form as illustrated, is providecl with a guide rod 1 9 adapted to extend through an drical part 15, and'is biased by" resilient means, as the spring. 22, towards a limiting chamber .and associated contact The explosionchamber, which is mounted upon the -depending portion 3 of the adapter, comprises a cover member 4 secured in any sutable manner to the portion j explosion structure.

25, to the lowe end with an-'o ening 26 through which 3 and a cylindrical steelcasing 5 forming' they main part of'theichamber clamped vto and supported by the cover member for en-Q is mounted an insulating throat bushing 6A rod -8 comprising su porting and? contact annular limiting shoul er 16 and a reduced` aperture 20 1n the end portion 21 of the cylin of thecontact 'ably secured, asby threaded engagement at member 12, and is provided-at its i 11, cylindrical in form, is

oo lThe lower portion of sov The.

the lower part oft e contact member may 100 extend or protrude whenin itslimiting position. Mounted within the member 24 and disposed circumferentially of the contact member, are conducting means, as the contact segments 27; resiliently biased by Springs 28 into conducting engagement wit the contact member. The conducting seg- :ments are electrically connected, as by the tact 'rod 8, u n closure ofthe breaker, moves lulpwardly into the explosion chamber rough the iiared opening in the :throatb bushing 6 and abuts the surface '18 of the contact memberfso that 'initial contact is thereby established.`- The spring 22 is so adjusted that it is under initial tension, thereby insuring firm contact pressure betweeng the abutting surfaces at the moment of contact so as to minimize the effects a of the contact rod int of burning due to. .insuiiicient' contact ressure. Upon further closing movement o the contact rod, the`l member 18 is :forced upwardly -against the tension of spring 22 so that the contactrod 8,;which moves within the retaining portion 24, is now in conductih engagement with the segments 27. In the y closed osition of the switch, the abuttingsurfaees o the rod 8 andmember 18 are disposed above the segments 27 so that the se ents'en ge the sides e norma current carrying positionof the switch..

Upon opening the switch, the contact rod 8 starts to descend; and acceleration thereof during the'opening movement is aided by the compressed spring 2 As the rod descends the contact member 18 'remains in following abutting engagement with the rod, so that the conductlng engagement between the segments is transferred from the rod to the contact member. IDueto the factv that the movement j .of the contact member is not checkeduntil the abutting end thereof has passed beyondvthe conducting segments and beyond the member l24-it will be apparent that the final arcing must' take place between the said abutting surfacev 18 and the end of the contact rod 8. Accordingly, the effects of the arc are confined to contact surfaces which are not utilized during normal operation of the switch.

- Since the sides of the contact -rod 8 remain comparatively free of the effects of arcing, and since the conducting segments 27 are protected from the eiects of arcmg by the' contact member 18, it will be apparent that the switch parts during closure thereof are in clean conducting'engagement with each other, thereby minimizing the effects of heat- 4by Letters Patent of the United States is:

ing vdue to high resistance contact engage- -ment. As the efects'of arcing on the con# tact member 18 are localized at the abutting surface 18', the sides of the contact member which are in sliding engagement with the l'conducting segments 27 are likewise main-v tained clean and free of burning.

It shall be understood that my invention is not -limited to the specific details of construction and arrangement thereof herein illustrated, and that changes or modifications may occur to on@ skilled in the art without departirrgfrom the spirit of my invention.

What I claim as new and desire to secure '1. Switch contact structure for large 'capacitycircuit breakers comprising a contact member mounted forl reciprocal movement, conducting contact' segments disposed circumferentially around sald member andms adapted to be resilientl-y biased into engagement therewith, and a movable contacterod adapted initially to abut one end." of the contact member and thereafter move into enagement with 4said contact segments, the initial and final contact engagement u on .closure and opening-of the circuit brea er being at said abutting surfaces.

2. Contact structure for large capacity switches of the fluid-break type comprising a stationary contact retainer,-a contact member guided therein for vertical movement,/ cofnductin segments mounted within said retainer clrcumferentially. of said member and adaptedto be resiliently biased into engagement therewith, resilient means for urging the contact member into position to be `engaged by said conducting se ents, and a movable contact rod adapted iiiing closure ofthe switch `initiallyto abut one end of the contact member' and P'thereafter lto be moved against the bias of said resilient means into conductil g engagement with vsaid segments.

3. Contact structure for -large capacity switches of the fluid-break typ e comprising a stationary Vcontact retainer, a contact member slidably mounted within 'said retainer, va spring for resiliently biasing said member towards a limiting position, conducting4 segments mounted within 'said retainer circumferentiallyi of the contact member and resiliently biased into conducting engagement 'with said member when it is in its limiting position, anda movable Contact rod adapted initially to` abut said contact member duringV closure ofthe switch whereby the Contact rod upon further movement overcomes the biasswitches of the fluid-break typ siring a'nd moves intb said retainer ucting engagement with 'said scg- 125 e comprising electrically connecting'the contact member' to the contact retainer, and a movable con- `tact rod adapted initially to 4'abut Ione end of the contact member u on closure of the switch and to engage within the contact retainer said conducting means when the switch isy in its fully closed position, said spring being under initial tension whereby the initial contactengagement at said abutting surfaces is effective to prevent burning of the contacts. r

5. In an oil circuit breaker comprising an explosion chamber and a movable contact rod adapted to make and break the circuit within said chamber, coacting contact structure mounted within said ex losion chamber for the movable contact ro comprising a contact retainer of conducting material, a contact member guided for reciprocal movement therein; and a spring for urgingsaid contact 3o abutting surfaces.

"member, into a limiting position whereby a portion thereof extends beyond the contact retainer, said movable contact rod adapted to abut said extending portion of :he. f :ontact member so that arcing during opening of the breaker is substantially 'confined to said 46. In an oil circuit breaker comprising lan explosion chamber and a movable contact rod adapted to makeand break the circuit L'within said chamber, coacting contact struc- `ture mounted within the explosion chamber for the movable contactrodcomprising a stationary contact retainer, a contact membermounted therein for reciprocal movement, conducting means within saidretainer adapted to be in conducting en agement with the contact member, and a spring for urging said/contact member into a limiting position whereby'it is in engagement with the conducting means, said movable contact rod adapted during 'closing movement of the switch initially to abut one end of -tlie contact member and to move the -same against the bias of said spring so that the contact rod engages 'the conducting means in the fully closed position of the breaker. 7. In an oil circuit breaker -comprising an explosion chamber and a 'movable contact rod adapted to make and break the circuit` within said chamber,'coacting contact structure mounted within the explosion chamber comprising a movable contact member, con.- ductiig means adapted to be in Sliding engagemexlt with said member for carrying thecurrent traversing said bre'aker, and a. spring ,for urging said member into a current-carrying position, said movable contact rod adaptedfto abut said .member in' its current carry'' ing position upon making and breaking of the circuit vwhereby arcing is substantially when it is in its closed circuit position where- A by the conducting means and contact rod are 7'0 in full current carrying engagement'.

8. In an oil circuit breaker comprising an explosion chamber and a movable contact.

rod arranged to make and break the circuit within said chamber, coacting butt contact structure mounted within said explosin chamber comprisin a contact retainer of conducting materia, a cylindrical contact' member guided for reciprocal movement therein, and a s ring for urging said contact member into fo Alowing enga ment with said contact rod and towards a 'miting position with respect to said'contact retainer, said movable contact rod adapted to abut the coactin4 surface 'of' said contact member during t e switch closing movement and move said contact member4 against the bias of said sprin made-and fina ly broken at said butt contact surfaces. l h Iiuiltness lvliereof` lave hergito set my an tis-2t a o eruar 0.

WYiimAM KYRA to so that contact is initially los las 

